Intracellular dynamics in rotavirus-like particles production: Evaluation of multigene and monocistronic infection strategies

Spodoptera frugiperda-9 (Sf-9) cells were infected by recombinant baculoviruses coding for viral protein 2 (VP2), VP6 and VP7 for the production of triple layered rotavirus-like particles (Rota VLPs). Single and co-infection experiments were performed using multigene and/or monocistronic vectors at a multiplicity of infection (MOI) of 5 pfu/cell for each individual gene. For a deeper understanding of the regulatory/controlling mechanisms involved in this process, measurements of intracellular viral DNA (vDNA), mRNA and viral proteins (VPs) were taken at different times post-infection (hpi). A simple mathematical model was then applied to the experimental data in order to evaluate the dynamics of intracellular events (infection, vDNA replication, mRNA synthesis and VP production) with the different strategies performed. The results of individual infection strategies were compared in order to understand the intrinsic relationship between VP production, type of recombinant baculovirus (multigene or monocistronic vector) and type of gene. The overall results show vDNA replication and transcription rates about 50% slower in the multigene experiments than in the monocistronic experiments. In terms of Rota VLPs synthesis, the M2/6/7 single-infection strategy reports VP2 limitation and excess of VP7 while the co-infection strategy, Co2 + 6 + 7, results in VP7 limitation. Finally, possible control scenarios that may lead to the increase of Rota VLP's productivity in co-infection experiments are discussed.